157 / 168
PAGE
155
UIMC
Unintended Flight in IMC
USOS
Undershoot/overshoot
UNK
Unknown or undetermined
WSTRW
Windshear or thunderstorm
ATM Accident Categories Acronyms
Accident categories can be used to classify occurrences at a high level to permit analysis of the data. The CICTT
has developed the accident categories used in this Annual Safety Review. For further details on this team and the
accident categories please see the website
(http://intlaviationstandards.org/index.html).
CLR
Deviation of ATC Clearance
IS
Inadequate Separation
MAC
Mid‑Air Collision
SMI
Separation Minima Infringement
UAP
Unauthorised Penetration of Airspace
RI
Runway Incursion is an occurrence involving the incorrect presence of an aircraft, vehicle, or
person on the protected area of a surface designated for the landing and take‑off of aircraft.
COL
Collision with a vehicle, person or aircraft, while an aircraft is on the ground